Agreement between two methods of clinical measurement can be quantified using the
differences between observations made using the two methods on the same subjects. The …

We often want to compare two estimates of the same quantity derived from separate
analyses. Thus we might want to compare the treatment effect in subgroups in a randomised …

In recent years odds ratios have become widely used in medical reports—almost certainly
some will appear in today's BMJ. There are three reasons for this. Firstly, they provide an …

In clinical measurement comparison of a new measurement technique with an established
one is often needed to see whether they agree sufficiently for the new to replace the old …

Methods of analysis used in the comparison of two methods of measurement are reviewed.
The use of correlation, regression and the difference between means is criticized. A simple …

Many quantities of interest in medicine, such as anxiety or degree of handicap, are
impossible to measure explicitly. Instead, we ask a series of questions and combine the …

Many published papers include large numbers of significance tests. These may be difficult to
interpret because if we go on testing long enough we will inevitably find something which is …

When comparing a new method of measurement with a standard method, one of the things
we want to know is whether the difference between the measurements by the two methods is …

Statistics Notes Page 1 are successful doctors may then be prepared to invest more time in
them. Further consideration should be given to new ways that general practitioners can deliver …

The whole point of a diagnostic test is to use it to make a diagnosis, so we need to know the
probability that the test will give the correct diagnosis. The sensitivity and specificity 1 do not …